IF YOU HAVE A MAGIC BUTTON 27MHZ 1 BUTTON LIKE THAT PICTURED ABOVE, IT WILL HAVE DIP SWITCHES (LITTLE WHITE BLOCKS THAT ARE INDIVIDUALLY NUMBERED) INSIDE THE BACK COVER.  YOU CAN REPLACE YOUR MAGIC 1 BUTTON REMOTE WITH A MAGIC DUO 2 BUTTON REMOTE. 

IF YOUR OLD MAGIC REMOTE HAS 9-10 DIP SWITCHES: REPLACE IT WITH THE MAGIC DUO 2 BUTTON REMOTE WITH 10 DIGITS (SHOWN BELOW).

IF YOUR OLD MAGIC REMOTE HAS 12 DIP SWITCHES: REPLACE IT WITH EITHER THE MAGIC DUO 2 BUTTON REMOTE WITH 12 DIGITS, OR THE SMALLER ELSEMA KEY301 MINI REMOTE (BOTH SHOWN BELOW).